// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "base/supports_user_data.h"

#include "base/memory/ptr_util.h"

namespace base {

SupportsUserData::SupportsUserData()
{
    // Harmless to construct on a different execution sequence to subsequent
    // usage.
    sequence_checker_.DetachFromSequence();
}

SupportsUserData::Data* SupportsUserData::GetUserData(const void* key) const
{
    DCHECK(sequence_checker_.CalledOnValidSequence());
    DataMap::const_iterator found = user_data_.find(key);
    if (found != user_data_.end())
        return found->second.get();
    return NULL;
}

void SupportsUserData::SetUserData(const void* key, Data* data)
{
    DCHECK(sequence_checker_.CalledOnValidSequence());
    user_data_[key] = WrapUnique(data);
}

void SupportsUserData::RemoveUserData(const void* key)
{
    DCHECK(sequence_checker_.CalledOnValidSequence());
    user_data_.erase(key);
}

void SupportsUserData::DetachFromSequence()
{
    sequence_checker_.DetachFromSequence();
}

SupportsUserData::~SupportsUserData()
{
    DCHECK(sequence_checker_.CalledOnValidSequence() || user_data_.empty());
    DataMap local_user_data;
    user_data_.swap(local_user_data);
    // Now this->user_data_ is empty, and any destructors called transitively from
    // the destruction of |local_user_data| will see it that way instead of
    // examining a being-destroyed object.
}

} // namespace base
